SCCE modified transgenic mammals and their use as models of human disease

Abstract

Genetic evidence that an imbalance in the activity of serine proteases can cause severe skin disease has recently been presented. The serine protease SCCE is preferentially expressed in cornifying epithelia. Increased expression of SCCE in psoriasis has previously been reported. Increased SCCE expression also in chronic lesions of atopic dermatitis is described herein. Transgenic mice expressing human SCCE in suprabasal epidermal keratinocytes were found to develop pathological skin changes with increased epidermal thickness, hyperkeratosis, dermal inflammation, and severe pruritus. The results strengthen the idea that SCCE may be involved in the pathogenesis of inflammatory skin diseases, and may offer a new therapeutic target.

1. A transgenic mouse, having integrated within its genome a nucleotide sequence (SCCE-construct) comprising a heterologous nucleotide sequence coding for a human stratum corneum chymotryptic enzyme (SCCE), operably linked to a SV40 early promoter that drives expression of said heterologous nucleotide sequence in skin, wherein the mouse exhibits epidermal hyperplasia and hyperkeratosis and a mild cellular inflammatory reaction of the skin. 
     
     
       2. A transgenic mouse according to  claim 1  wherein said operably linked SV40 early promoter drives expression of scce in epidermis. 
     
     
       3. A transgenic mouse according to  claim 1 , wherein the DNA sequence codes for the human SCCE corresponding to amino acid no. 23 through no. 253 of the amino acid sequence shown in SEQ ID NO. 2. 
     
     
       4. A tranagenic mouse according to  claim 1 , wherein the DNA sequence codes for the human SCCE corresponding to amino acid no. 30 through no. 253 of the amino acid sequence shown in SQ ID NO. 2. 
     
     
       5. A tranagenic mouse according to  claim 1 , wherein the DNA sequence codes for the human SCCE shown in SEQ ID NO. 2. 
     
     
       6. A transgenic mouse according to  claim 1 , wherein the heterologous nucleotide sequence is SEQ ID NO:1. 
     
     
       7. A method for making a transgenic mouse according to  claim 1 , the method comprising
 (a) constructing and amplifying said heterologous nucleotide sequence,  
 (b) introducing said heterologous nucleotide sequence into a cell from a mouse, where said cell is selected from the group consisting of a mouse ovum, a mouse embryonic cell, and a mouse embryonic stem cell.  
 (c) using said cell or the progeny of said cell to create a number of putative transgenic mice, and  
 (d) selecting said mouse having said heterologous nucleotide sequence integrated within its genome.  
 
     
     
       8. A method for making a transgenic mouse according to  claim 7  wherein said operably linked promoter drives expression of scce in epidermis. 
     
     
       9. A method according to  claim 7  comprising introducing the SCCE-construct into an ovum or embryo of the mouse. 
     
     
       10. A method according to  claim 7  comprising microinjecting the SCCE-construct into embryonal stem cells of the mouse. 
     
     
       11. A method according to  claim 7  comprising microinjecting the SCCE-construct into C57BL/6JxCBA-f2 mouse ova or embryos. 
     
     
       12. A method according to  claim 7  comprising introduction of the SCCE-construct into C57BL/6JxCBA-f2 mouse ova or embryos and breeding the resulting mice with C57BL/6JxCBA or with C57BL/6J to obtain transgenic progeny and stable mouse lines. 
     
     
       13. A method of identifying a compound or composition effective for the prevention or treatment of epidermal hyperkeratosis, acanthosis, epidermal inflammation, dermal inflammation and pruritus, the method comprising
 (a) administering a compound or composition to a transgenic mouse according to  claim 1 ,  
 (b) evaluating the appearance of the skin and/or the behavior of a mouse treated according to step (a), and  
 (c) comparing the appearance of the skin and/or the behavior of a treated mouse with an untreated control mammal,  
 (d) identifying the compound or composition as being effective for the prevention or treatment of epidermal hyperkeratosis, acanthosis, epidermal inflammation, dermal inflammation and pruritus.  
 
     
     
       14. A method according to  claim 13  of identifying a compound or composition effective for the prevention or treatment of epidermal hyperkeratosis. 
     
     
       15. The method of  claim 7  in which said introduction is by electroporation, transfection, microinjection or viral infection. 
     
     
       16. The method of  claim 7  in which said introduction is by microinjection. 
     
     
       17. The method of  claim 16  in which the microinjection is into a mouse ovum.